Delegated Directory Pruning for Crowd is available in Crowd 4.3 and later as a native feature so there’s no need to download this app if you’re using this version.
This plugin allows to optimize your license usage by periodically cleaning inactive users from your delegated directories. After configuring pruning for a delegated directory the plugin will periodically check if the directory contains any users who have been deactivated or removed from the remote directory.
By default such users will be deactivated in Crowd. It is also possible to enable "hard delete" mode, in which users who have been deleted in the remote directory will also be deleted in Crowd.